Obtain the cooperation of staff at the designated hospitals in the Washington area. Identify all cases, aged 21-80, of ovarian cancer diagnosed between July 1, 1978, and June 30, 1981, in the designated hospitals. Select a number of controls approximately equal to the number of identified cases from each hospital of each race and age category. Contact the physician in charge of each case and each control to obtain his permission to approach the patient for an interview. Contact each patient whose physician has given permission to arrange an interview. Interview each respondent. Ask each respondent for release of specific medical information. Interview a sample of gynecologists and staff of fertility clinics. Validate a random sample of 20% of the interviews with patients. Record data from medical charts for cases and controls. Ask the pathologist for each case to allow one or more of the pathologic slides to be examined by the consulting pathologist for the study.